JP5897814B2 - Powder deposition layer angle measuring device - Google Patents

Description

  The present invention relates to a powder deposition layer angle measuring apparatus.

  The physical property value of the powder is measured with various parameters such as repose angle, collapse angle, spatula angle, loose / hard bulk density, degree of compression, degree of aggregation, degree of dispersion, and difference angle. Examples of the apparatus for measuring the angle of the powder deposition layer such as the repose angle and the spatula angle can be found in Patent Documents 1 and 2.

  The apparatus described in Patent Document 1 is for measuring at least one of the physical properties of a powder, such as repose angle, collapse angle, looseness / hardness bulk density, compression degree, spatula angle, cohesion degree, dispersion degree, and difference angle. Measuring means and control means for performing control and arithmetic processing necessary for measurement by the measuring means are provided. The measuring means includes an angle measuring jig that rotationally drives the angle measuring arm with a pulse motor so as to be parallel to the inclined surface of the deposited sample powder. The control means controls the driving of the pulse motor with the driving pulse, and calculates the angle of the angle measuring arm by counting the number of driving pulses.

  The device described in Patent Document 2 includes a camera on a base. When the angle of repose is measured, the angle of repose measurement table is placed in front of the camera with the backlight panel in the back. When measuring the spatula angle, place the spatula with the backlight panel in front of the camera. When the image is taken with a camera, a silhouette image of the powder accumulation layer on the angle of repose measurement table or a silhouette image of the powder accumulation layer on the spatula can be obtained. This image is analyzed by a computer to determine the inclination angle of the powder deposit layer.

Japanese Patent No. 2798827 Japanese Patent No. 4155542

  When the angle of the powder accumulation layer is obtained by an image analysis technique as in the device described in Patent Document 2, there is a situation in which the light inserted from outside the device becomes a disturbance factor to hinder the analysis of the image, or the analysis accuracy is lowered. Often occurs. However, in general, the environment in which this type of device is used has a bright illumination, and it is difficult to block outside light.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an apparatus for measuring an angle of a powder deposition layer capable of performing accurate angle measurement without being affected by external light.

  The powder deposition layer angle measuring apparatus of the present invention includes a camera, a backlight panel disposed at a position facing the camera, a powder deposition layer support device disposed between the camera and the backlight panel, Analyzing the silhouette image of the powder accumulation layer photographed by the camera, and comprising an image analysis device for obtaining the angle of the powder accumulation layer, the backlight panel emits light in a predetermined wavelength range, The camera is combined with an optical filter having a high transmittance with respect to the emission wavelength region of the backlight panel.

  In the powder deposition layer angle measuring apparatus of the present invention, the backlight panel is a light source having an emission spectrum peak at 450 nm to 550 nm.

  In the powder deposition layer angle measuring device of the present invention, the backlight panel includes a combination of a light transmission panel having a light guide function and a light diffusion function, and an LED for irradiating light to an end surface of the light transmission panel.

  In the powder deposition layer angle measuring apparatus of the present invention, the light transmission panel is configured by combining a light guide plate and a diffusion plate.

  In the powder deposition layer angle measuring apparatus of the present invention, the optical filter is a bandpass filter having a maximum transmittance of 30% or more with respect to a peak wavelength of the backlight panel.

  In the powder deposition layer angle measuring apparatus of the present invention, an openable / closable cover is provided to cover the camera and the powder deposition layer support device, and the backlight panel is attached to the cover.

  According to the present invention, the backlight panel emits light in a predetermined wavelength range, and the camera is combined with an optical filter having a high transmittance with respect to the emission wavelength range of the backlight panel. Light other than the emitted light basically does not become incident light on the camera. For this reason, a silhouette image of the powder deposition layer is formed only by light from the backlight panel, and a silhouette image having an accurate shape is obtained. The analysis of the silhouette image by the image analysis apparatus is also accurate, and the angle measurement accuracy is improved.

It is a schematic front view of a powder deposition layer angle measuring device. It is a schematic side view of a powder deposition layer angle measuring device. It is a schematic sectional drawing of a backlight panel, and it is seen from the side surface direction. It is a schematic sectional view of a backlight panel and is seen from the front direction. It is a top view of the LED array used for a backlight panel. It is explanatory drawing of the concept of image processing. It is a block block diagram of a powder deposition layer angle measuring device. It is a schematic sectional drawing explaining a repose angle measurement. It is a schematic sectional drawing explaining a spatula angle measurement.

  The two major elements constituting the appearance of the powder accumulation layer angle measuring apparatus 1 are a main body 2 and a cover 3 covering the front part thereof. The main body 2 is formed by enclosing the outside of a gantry structure (not shown) with a casing 4 made of sheet metal, and is supported on a support surface by a plurality of support legs 5 whose heights can be adjusted. A main part of the cover 3 is formed of a transparent synthetic resin, and is attached to both left and right side surfaces of the main body 2 with a pair of left and right arms 6. The tip of the arm 6 serves as a fulcrum part 7 connected to the main body 2, and the cover 3 rotates in a vertical plane around the fulcrum part 7.

  When the cover 3 is lowered, the solid line state of FIG. 2 is obtained. At this time, the space enclosed by the cover 3 becomes the measurement chamber 10 shown in FIG. As described above, since the main part of the cover 3 is transparent, the inside of the measurement chamber 10 can be seen even when the cover 3 is lowered, and the operator can visually check the state of the sample and observe the influence of dust. Measurement work can be done without receiving it.

  A handle portion 3a is formed on the front surface of the cover 3, and a hand can be put on the cover 3 to raise the cover 3 to the position of the phantom line in FIG. When the cover 3 is pulled up to the position of the phantom line in FIG. 2, the cover 3 remains in that position even when the hand is released. In this way, after the measurement chamber 10 is opened, the operator cleans up the measured sample and tools used for the measurement, sets a new measurement work, performs maintenance and inspection work, and the like. When it is no longer necessary to keep the measurement chamber 10 open, the cover 3 is lowered. A damper is combined with the shaft that supports the cover 3 at the fulcrum portion 7. If the hand is released during the lowering, the cover 3 descends slowly and closes gently without giving an impact.

  A camera 20 and a backlight panel 30 (see FIG. 3) are arranged with respect to the measurement chamber 10 so as to face each other. A powder deposition layer support device is disposed between the camera 20 and the backlight panel 30, which will be described later.

  The camera 20 is fixedly installed in the measurement chamber 10 at a certain height on the left side when viewed from the front. For example, UCAM-DLU130H series (1.3 million pixels) sold by ELECOM as a WEB camera, BSW13D06H series (1.3 million pixels) sold by Buffalo as a WEB camera, and global sold by Microvision, Inc. Shutter CMOS board camera (monochrome) MCM-4304 (300,000 pixels), monochrome progressive scan camera CM-030GE (300,000 pixels) sold by JAI Corporation, progressive CMOS color (BW) sold by Art Ray A camera ARTCAM-036MI (360,000 pixels) can be used.

  The backlight panel 30 is disposed at the right end of the measurement chamber 10. The backlight panel 30 is attached to the backlight panel support 6a (see FIG. 2) formed on the right side of the cover 3 as viewed from the front, specifically, the right arm 6. The cover 3 is formed with a rectangular opening corresponding to the rectangular light emitting surface of the backlight panel 30, and the light emitting surface of the backlight panel 30 is exposed to the inside of the measurement chamber 10 through the opening.

  As the cover 3 rotates, the backlight panel 30 also rotates. When the cover 3 is closed, the backlight panel 30 faces the camera 20. Thus, by using the cover 3 as an attachment member for the backlight panel 30, it is not necessary to separately provide an attachment member for the backlight panel 30, and the configuration can be simplified.

  The backlight panel 30 has the configuration shown in FIGS. Reference numeral 31 denotes a rectangular parallelepiped case that is flat in the left-right direction when viewed from the front. The case 31 is made of a metal with good heat dissipation, for example, aluminum sheet metal. The case 31 has an opening on the left side when viewed from the front, and a reflection sheet 32 and a light transmission panel 33 having a light guide function and a light diffusion function are inserted through the opening. In the embodiment, the light transmission panel 33 is configured by combining two plates. That is, the light guide plate 33a and the diffusion plate 33b. The vertical surface on the left side of the diffusion plate 33b when viewed from the front is the light emitting surface 30a of the backlight panel 30.

  The light emitting surface 30a generates uniform surface light by a mechanism similar to that employed in the backlight of a mobile phone. A light emitting diode (hereinafter referred to as “LED”) 34 illuminates the light emitting surface 30a. A substrate 35 on which a plurality of LEDs 34 are attached at predetermined intervals is disposed below the light transmission panel 33. The LED 34 irradiates light to the end surface of the light transmission panel 33, specifically, the lower end surface of the light guide plate 33a. The light changes its direction inside the light guide plate 33a and enters the diffusion plate 33b. The light diffuses inside the diffusion plate 33b, and the light emitting surface 30a shines evenly and uniformly.

  The LED 34 is of a monochromatic light emission type exhibiting high luminous efficiency in a specific wavelength range, and the emission wavelength range of the light emitting surface 30a is also a predetermined wavelength range close to the specific wavelength range. The camera 20 is combined with an optical filter 21 having a high transmittance with respect to the light emission wavelength region of the backlight panel. As the optical filter 21, what is generally known as a long pass filter, a short pass filter, or a band pass filter can be used.

  The light source of the backlight 30 and the optical filter 21 are determined by the measurement environment. For example, when the external light is mainly sunlight, since the emission spectrum of sunlight has a peak mainly at a wavelength near 500 nm, use an optical filter 21 that can block at least light in that wavelength range, If a light source having a peak wavelength in a wavelength region that is not blocked by the optical filter 21 is used as the light source of the backlight 30, the influence of external light can be reduced during measurement. In addition, when the external light is mainly light from a fluorescent lamp, the emission spectrum of the fluorescent lamp has a peak mainly at wavelengths around 440 nm, 550 nm, and 620 nm, so that the optical filter 21 has at least the most of those wavelength ranges. If a light source with a high emission intensity that can block wavelengths near 550 nm is used, and a light source having a peak wavelength in a wavelength range that is not blocked by the optical filter 21 is used as the light source of the backlight 30, the influence of external light is reduced during measurement. can do.

  When the emission spectrum of the light source of the backlight 30 has a plurality of peaks, an optical filter 21 that does not block at least the peak wavelength with the highest emission intensity among those peaks is selected.

  The light source of the backlight 30 preferably has a peak wavelength in the range of 400 nm to 700 nm. More preferably, it has a peak wavelength in the range of 450 nm to 550 nm, more preferably 460 nm to 480 nm. In such a peak wavelength region, for example, a blue LED or a white LED that is relatively inexpensive and easily available can be used as a light source.

  The maximum transmittance of the optical filter 21 is preferably 30% or more with respect to the peak wavelength of the light source of the backlight 30, and more preferably 50% or more. Angle measurement is possible even if the maximum transmittance is less than 30%, but the photographed image becomes dark and the accuracy of angle measurement may be reduced. When a band pass filter is used as the optical filter 21, the half width is preferably 5 nm to 120 nm, more preferably 5 nm to 40 nm. Although it can be used even if the half-value width is larger than 120 nm, in this case, the wavelength range to be blocked is widened, so the choice of the light source of the backlight 30 is limited. If the full width at half maximum is 40 nm or less, options for the light source of the backlight 30 are further expanded.

  The imaging signal of the camera 20 is input to the control device 40 shown in FIG. The control device 40 is positioned as a kind of computer and outputs control signals to the camera 20 and the backlight panel 30. The control device 40 includes an image analysis device 22, and the image analysis device 22 analyzes the captured image.

  An image captured by the camera 20 is as shown in FIG. An image consists of a collection of many pixels. FIG. 6 shows a situation in which a conical or chevron-shaped powder deposit layer is present on a repose angle measuring table or a spatula angle measuring blade.

  From the image of FIG. 6, the inclination angle of the powder deposition layer can be obtained using a calculation formula as disclosed in Japanese Patent No. 4155542.

  Since the backlight panel 30 emits light in a predetermined wavelength range, and the camera 20 is combined with an optical filter 21 having a high transmittance with respect to the emission wavelength range of the backlight panel 30, other than the light emitted by the backlight panel 30. Is basically not incident on the camera 20. For this reason, a silhouette image of the powder deposition layer is formed only by the light from the backlight panel 30, and a silhouette image having an accurate shape is obtained. The analysis of the silhouette image by the image analysis device 22 is also accurate, and the angle measurement accuracy is improved.

  The powder deposition layer angle measuring device 1 is provided with an impact applying device 50 (see FIG. 8) used at the time of collapse angle measurement. Here, the collapse angle is an inclination angle of the powder accumulation layer after the powder accumulation layer forming the angle of repose has changed its shape with an impact.

  The impact applying device 50 includes a bracket 51 disposed horizontally inside the housing 4 and a guide pole 52 that rises vertically from the bracket 51. A repose angle measurement table and a spatula angle measurement blade, which will be described later, are connected to the bracket 51. An impact weight 53 is supported on the guide pole 52 so as to freely move up and down. When the impact weight 53 is lifted and dropped onto the bracket 51, vibration is generated in the bracket 51, and the vibration is transmitted to the repose angle measurement table and the spatula angle measurement blade.

  The powder deposition layer angle measuring device 1 is provided with a vibration device that applies sample powder to a vibration sieve. The main body portion of the vibration device exists in the housing 4 and only the sieve mounting frame 60 supported by the main body portion protrudes into the measurement chamber 10 as shown in FIG. The sieve mounting frame 60 is subjected to vertical vibration by an electromagnet 61 shown in FIG.

  As shown in FIG. 7, a display device 70 is connected to the control device 40 in addition to the already-described components such as the camera 20, the image analysis device 22, the backlight panel 30, and the electromagnet 61. The display device 70 is configured by an external monitor device or the like, and displays measurement data and calculation results.

  Next, how the powder deposition layer angle measuring apparatus 1 is used will be described with reference to FIGS. 8 and 9.

  FIG. 8 shows a setting for repose angle measurement. A sieve 80 is attached to the upper surface of the sieve mounting frame 60. A sieve retainer 81 is stacked on the sieve 80, a repose angle measuring funnel 82 is attached to the lower surface of the sieve attachment frame 60, and these are fixed to the sieve attachment frame 60 with fasteners 93. A bracket 84 that supports an angle of repose measurement table 83 that is a powder deposition layer support device is connected to the bracket 51 of the impact applying device 50. Under the repose angle measurement table 83, a bat 85 for receiving a sample spilled therefrom is arranged. The bat 85 is supported by a vertical support shaft 86 protruding from the inside of the housing 4 into the measurement chamber 10. The support shaft 86 is moved up and down by a support shaft lifting motor 87 shown in FIG. The support shaft lifting motor 87 is driven by a motor driver 88.

  When sample powder is put into the sieve 80 and the sieve mounting frame 60 is vibrated, the sample powder that has passed through the sieve 80 falls from the repose angle measurement funnel 82 and accumulates in a cone shape on the repose angle measurement table 83. . A silhouette image of the powder accumulation layer is captured by the camera 20, and an angle of repose is obtained by image analysis. After the angle of repose is measured, the powder deposition layer is crushed by impact by the impact applying device 50, and the collapse angle is measured. Thereafter, the difference angle is calculated. Here, the difference angle is an angle obtained by subtracting the collapse angle from the repose angle, and the jet property (flashing property) of the powder can be estimated from the size.

  FIG. 9 shows a setting for measuring a spatula angle. The repose angle measurement funnel 82 in the repose angle measurement setting in FIG. 8 is replaced with a spatula angle measurement chute 89, and the combination of the repose angle measurement table 83 and the bracket 84 that supports it is also a powder deposit. It is replaced with a combination of a spatula angle measuring blade 90 which is a layer support device and a bracket 91 which supports the blade. At this time, a surrounding frame 92 surrounding the spatula angle measuring blade 90 is installed on the bat 85.

  When the bat 85 is lifted up to a height at which the butt 85 is almost in close contact with the bracket 91, the sample powder is put into the sieve 80, and the sieve mounting frame 60 is vibrated. It falls from 89 and is piled on the spatula angle measuring blade 90. When the bat 85 and the surrounding frame 92 are lowered when the spatula angle measuring blade 90 is completely buried in the sample powder, a continuous mountain-shaped powder deposition layer remains on the spatula angle measuring blade 90. A silhouette image of the powder accumulation layer is captured by the camera 20, and an inclination angle is obtained by image analysis. Thereafter, the powder deposition layer is crushed by an impact by the impact applying device 50, and the tilt angle after the collapse is measured. And the average value of the inclination angle before collapse and after collapse is calculated. This value is the spatula angle.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  Angle measurement was performed using a measuring device (powder property measuring device “Powder Tester” manufactured by Hosokawa Micron Corporation) for evaluating the physical properties of the powder. The measurement was performed in an environment with an illuminance of 610 lux to 6300 lux with external light mainly being fluorescent light. As the LED 34, a blue LED having a peak wavelength in the range of 460 nm to 480 nm was used. As the optical filter 21, a bandpass filter having a center wavelength of 460.0 ± 2 nm, a half width of 6.0 ± 2 nm, and a maximum transmittance of 30.0% or more was used. In the comparative example, the measurement was performed under the same conditions as in the example except that no optical filter was attached to the camera. It should be noted that the higher the illuminance of the measurement environment, the higher the intensity of external light, and adverse effects will occur during measurement.

  The experimental results of the angle measurement are shown in Table 1. In Comparative Example 1, angle calculation was possible under 610 lux, but under 750 lux in Comparative Example 2, binarization processing caused spots and slits to appear in the silhouette image, and the ridges and vertices of the silhouette image. Could not be detected, and the angle could not be calculated. On the other hand, in Examples 1 to 4, measurement was performed under 750 lux, 2200 lux, 4200 lux, and 6300 lux, respectively, and a predetermined angle measurement could be performed. Thus, angle calculation could be performed even in an environment of 6300 lux, which greatly exceeds 3000 lux, which is the illuminance under a normal measurement environment.

  The present invention is widely applicable to powder deposition layer angle measuring devices.

DESCRIPTION OF SYMBOLS 1 Powder deposit layer angle measuring device 2 Main body 3 Cover 10 Measurement room 20 Camera 21 Optical filter 22 Image analysis device 30 Backlight panel 33 Light transmission panel 33a Light guide plate 33b Diffusion plate 34 LED
40 control device 50 impact applying device 60 vibration plate 80 sieve 83 repose angle measurement table 90 spatula angle measurement blade 93 fastener

Claims (6)

A camera,
A backlight panel disposed at a position facing the camera;
A powder deposition layer support device disposed between the camera and the backlight panel;
Analyzing the silhouette image of the powder accumulation layer photographed by the camera, and obtaining an angle of the powder accumulation layer;
An optical filter that is combined with the camera and blocks a wavelength region near the peak wavelength of external light;
A powder deposited layer angle measuring device, characterized in that the backlight panel emits light having a peak wavelength in a wavelength range not blocked by the optical filter .   2. The powder deposition layer angle measuring apparatus according to claim 1, wherein the backlight panel is a light source having an emission spectrum peak at 450 nm to 550 nm. The powder deposition layer angle measuring device according to claim 1 or 2 , wherein the optical filter is a band pass filter having a maximum transmittance of 30% or more with respect to a peak wavelength of the backlight panel. An openable and closable cover is provided to cover the camera and the powder deposition layer support device, the backlight panel is attached to the cover, and the backlight panel faces the camera when the cover is closed. The powder deposition layer angle measuring device according to any one of claims 1 to 3 , wherein The powder cover layer angle measuring device according to claim 4 , wherein the cover is attached to a main body of the powder deposit layer angle measuring device with a pair of left and right arms . 6. The powder deposition layer angle measuring apparatus according to claim 5, wherein when the cover is pulled up to a predetermined position, the cover remains in that position even if the hand is released .

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